The invention relates to a construction, such as a pallet, provided with plate-like components of nailable material, for instance of wood chips, wood parts and/or wood fibers, plastic and the like which are pressed together with glue under pressure and/or with addition of heat to form such a plate-like component. At least two of said plate-like components, each of random thickness, are joined together on mutually facing surfaces using one or more nail elements to form a plate-like element. The nail element is embodied as a spatial body provided with nail-like fixing elements for connection to the surfaces of the upper and lower plate-like components.
Due to its composition and method of production, the plate material has a sufficiently high modulus of elasticity and sufficient capacity to withstand shear, pressure and tensile stresses and distribute them while being loaded for instance perpendicularly to the surface of the plate-like element.
Such a construction is disclosed in DE-U-8702655.4.
An object of the invention is to further improve the carrying capacity of such a construction and provides a construction which is distinguished in that the spatial body is formed as a framework from a flat wire mat which is folded along predetermined lines A, B, C parallel to the surfaces.
Since the nail element is a spatial body which is arranged between the upper and lower plate-like components of the construction, a good resistence against shearing of the assembly is achieved.
According to a main feature of the invention, a wire mat can be folded along predetermined lines to form the spatial construction. The nail-like fixing elements can be fixed to the spatial body in random manner but in case of a wire mat the invention further proposes cutting through predetermined wires of the flat mat. The cut parts are arranged to protrude outside of the spatial body after a folding of the mat, thus forming the nails of the fixing elements.
For some applications it is advantageous to fill the assembly with a foam material in a space formed between the upper and lower plates which embed the spatial body.
In order to optimize resistance against the nails being pulled out of the nailable material, the ends of the nails are given a chamfering, such that, during a pressing in, they preferably assume a so-called open-tulip position in the nailable material.
The invention further provides incorporating a nail element known from the Netherlands patent application number 9101725 on the joint face of the two nailable components, both having equal thicknesses to form a plate-like component being able to withstand a load perpendicularly to the surface which is four times the load which a component used singly can withstand.
In order to enable a still better absorption of pressure load, the plate-like body of a nail element can have a minimum of one reinforcing rib rolled-therein. The form of the rib can be a milled recess for a good fit in the nailable component.
In the case of nailable elements joined together from a minimum of three parts with nail elements, a nail element can also be arranged adjacent the lower element being the tensile zone of the plate-like component.
It is also possible to fix a nail element both in the assembly of at least three nailable elements on the joint face in the middle of the constituent parts and in the tensile zone of the assembly. Withstanding of a compression and a tensile stress can hereby be optimized.
As a result of the two described nailable components, when joined together the components are capable of withstanding a minimum of four times a pressure load, it is also possible to reduce the thickness dimension of the nailable plate material to a thickness sufficient to withstand a load suitable for a single nailable element. On the other hand, due to the ability to withstand a higher load, the option is present of allowing a heavier load on an identical surface.
A practical use of the assembly of the present invention is for the deck of a loading platform (pallet). In current practice standard pallets are usually constructed from wooden parts having a small width wherein the so-called top deck is first fixed to a so-called intermediate deck. This assembled pallet deck is then fixed with nails to wooden or plastic spacers. The number of spacers amounts to nine in order to make the pallet construction sufficiently rigid and stable. These spacers are placed such that each side of the rectangular form contains three spacers with one placed in the center of the pallet construction. At a prescribed length, the spacers leave space allowing access for forks of (internal) transport material such as fork-lift trucks from the ground or a substructure of the pallet. This known pallet construction having nine spacers allows fork access on each rectangular side and is called a four-way pallet. Pallet constructions are also known which have both a top deck and a bottom deck, so-called double-decker pallets. The spacers are then arranged between the intermediate decks.
The pallet construction according to the invention allows the nail element to join together the joint face of two nailable components of, for instance, rectangularly shaped plate material, along the diagonals of the rectangle. The nail elements, which may or may not be provided with reinforcing ribs, allow the utilization of a metal bush, which is pre-fixed to the nail element and has an internal screw thread to enable, for instance, a cylindrically formed spacer to be screwed on.
Since the joined together nailable components have such a great capacity to withstand pressure load, it is possible to fix only five spacers to the pallet deck, i.e. one on each of the four corners and one in the center of the pallet construction. This gives fork access to (internal) transport material on eight sides of the pallet, i.e. on the four rectangle sides in addition to the diagonal directions. It is then possible to speak of an eight-way pallet. The advantage of an eight-way access is that it achieves time-saving because, for instance, a pallet truck or fork-lift truck does not have to take an angle of 90xc2x0 in all cases.
Should still more rigidity be required of the pallet construction, a nail element can then also be pressed on the joint face on each rectangle side.
The pallet construction according to the invention can likewise be provided with a bottom deck. The spacers can be screwed in a simple manner to the bushes by giving them opposing threads.
Because the spacers are screwed onto a bush fixed to the nail element and are provided with a screw thread, it is also possible to couple these to, for instance, a rod of vibration-damping or vibration-absorbing material, consisting, for instance, of rubber and/or plastic. Instead of a rubber/plastic rod, it is also possible to couple to, for instance, a double-action hydraulic cylinder and, although this is not immediately obvious, to a construction with a gas spring. Since coupling to the bottom deck of a pallet is possible in a manner identical to coupling to the top deck of a pallet, the pallet can also be employed upside down while retaining vibration-damping and vibration-absorbing properties. The advantage of a thus constructed pallet is the possibility of, for instance, being able to adjust the rupture value of carton constructions which permit a lighter gram weight per unit. Since the construction of the spacer likewise has a good capacity to withstand shocks, also in horizontal direction, which may occur during use in a transport path, it will be possible to reduce the consequences of subsequent damage.
The invention will be further elucidated in the figure description hereinbelow of a number of embodiments.